You can stream content straight in the browser using Microsoft's Silverlight plug-in. And any already purchased content throug the Windows 8.1 app or on an Xbox One will be also available immediately for streaming. Content can be also purchased and streamed on the web, with the content then automatically available on Windows 8 and Xbox One.

Microsoft says that that HD quality playback is only available on Xbox One or Windows 8.1.

An Xbox Video app is expected to soon grace Windows Phones, though it will also lack HD playback.